Patients prescribed antibiotics in primary care may develop a resistance that lasts up to 12 months, according to research published online in the British Medical Journal.

It is widely recognised that resistance to antibiotics is a major threat to public health. However, according to the researchers, this is not seen by most clinicians or patients as a reason to refrain from using them, with many regarding the problem as minimal.

To address a lack of systematic reviews in the area, the authors analysed 24 existing studies of resistance in individual patients prescribed antibiotics in primary care, mainly for respiratory or urinary infections.

They found strong evidence that individuals prescribed an antibiotic in primary care for a respiratory or urinary infection develop a resistance. The effect is greatest in the month immediately after treatment, but may last for up to a year, and this residual effect may be a driver for high levels of resistance in the community.

The review provides the evidence needed to quantify the link between individual prescribing decisions and the problem of resistance, the authors conclude. They say it highlights that the only way to avoid the "vicious cycle of resistance" is to avoid the initial use of antibiotics wherever possible. However, they also call for more clinical trials to strengthen the evidence base.

In an accompanying analysis, two specialists in economics and health policy argue that new antibiotics to tackle multi-drug resistant bacteria are much needed. They show how financial incentives might be used to persuade drug companies to develop new antibiotics, and suggest that such action needs to be accompanied by efforts to tackle overuse of antibiotics, which is currently fuelling the spread of resistant bacteria.